use std::sync::Arc;

use agent_skills::GLOBAL_SKILLS_DIR_DISPLAY;
use auto_update::{AutoUpdater, release_notes_url};
use client::zed_urls;
use db::kvp::Dismissable;
use editor::{Editor, MultiBuffer};
use gpui::{
    App, DismissEvent, Entity, EventEmitter, FocusHandle, Focusable, TaskExt, Window, actions,
    prelude::*,
};
use markdown_preview::markdown_preview_view::{MarkdownPreviewMode, MarkdownPreviewView};
use prompt_store::rules_to_skills_migration;
use release_channel::{AppVersion, ReleaseChannel};
use semver::Version;
use serde::Deserialize;
use smol::io::AsyncReadExt;
use ui::{AnnouncementToast, ListBulletItem, SkillsIllustration, prelude::*};
use util::{ResultExt as _, maybe};
use workspace::{
    Workspace,
    notifications::{
        Notification, NotificationId, SuppressEvent, show_app_notification,
        simple_message_notification::MessageNotification,
    },
    workspace_error::{ErrorAction, ErrorSeverity, WorkspaceError},
};
use zed_actions::ShowUpdateNotification;

actions!(
    auto_update,
    [
        /// Opens the release notes for the current version in a new tab.
        ViewReleaseNotesLocally
    ]
);

pub fn init(cx: &mut App) {
    notify_if_app_was_updated(cx);
    cx.observe_new(|workspace: &mut Workspace, _window, cx| {
        workspace.register_action(|workspace, _: &ViewReleaseNotesLocally, window, cx| {
            view_release_notes_locally(workspace, window, cx);
        });

        if matches!(
            ReleaseChannel::global(cx),
            ReleaseChannel::Nightly | ReleaseChannel::Dev
        ) {
            workspace.register_action(|_workspace, _: &ShowUpdateNotification, _window, cx| {
                show_update_notification(cx);
            });
        }
    })
    .detach();
}

#[derive(Deserialize)]
struct ReleaseNotesBody {
    title: String,
    release_notes: String,
}

fn notify_release_notes_failed_to_show(
    workspace: &mut Workspace,
    _window: &mut Window,
    cx: &mut Context<Workspace>,
) {
    let url = release_notes_url(cx);

    struct ReleaseNotesError {
        url: Option<String>,
    }

    impl WorkspaceError for ReleaseNotesError {
        fn primary_message(&self) -> SharedString {
            "Couldn't load release notes".into()
        }
        fn severity(&self) -> ErrorSeverity {
            ErrorSeverity::Error
        }
        fn primary_action(&self) -> ErrorAction {
            self.url
                .clone()
                .map(|url| ErrorAction::link("View in Browser", url))
                .unwrap_or_else(ErrorAction::dismiss)
        }
    }

    workspace.show_error(ReleaseNotesError { url }, cx);
}

fn view_release_notes_locally(
    workspace: &mut Workspace,
    window: &mut Window,
    cx: &mut Context<Workspace>,
) {
    let release_channel = ReleaseChannel::global(cx);

    if matches!(
        release_channel,
        ReleaseChannel::Nightly | ReleaseChannel::Dev
    ) {
        if let Some(url) = release_notes_url(cx) {
            cx.open_url(&url);
        }
        return;
    }

    let version = AppVersion::global(cx).to_string();

    let client = client::Client::global(cx).http_client();
    let url = client.build_url(&format!(
        "/api/release_notes/v2/{}/{}",
        release_channel.dev_name(),
        version
    ));

    let markdown = workspace
        .app_state()
        .languages
        .language_for_name("Markdown");

    cx.spawn_in(window, async move |workspace, cx| {
        let markdown = markdown.await.log_err();
        let response = client.get(&url, Default::default(), true).await;
        let Some(mut response) = response.log_err() else {
            workspace
                .update_in(cx, notify_release_notes_failed_to_show)
                .log_err();
            return;
        };

        let mut body = Vec::new();
        response.body_mut().read_to_end(&mut body).await.ok();

        let body: serde_json::Result<ReleaseNotesBody> = serde_json::from_slice(body.as_slice());

        let res: Option<()> = maybe!(async {
            let body = body.ok()?;
            let project = workspace
                .read_with(cx, |workspace, _| workspace.project().clone())
                .ok()?;
            let (language_registry, buffer) = project.update(cx, |project, cx| {
                (
                    project.languages().clone(),
                    project.create_buffer(markdown, false, cx),
                )
            });
            let buffer = buffer.await.ok()?;
            buffer.update(cx, |buffer, cx| {
                buffer.edit([(0..0, body.release_notes)], None, cx)
            });

            let buffer = cx.new(|cx| MultiBuffer::singleton(buffer, cx).with_title(body.title));

            let ws_handle = workspace.clone();
            workspace
                .update_in(cx, |workspace, window, cx| {
                    let editor =
                        cx.new(|cx| Editor::for_multibuffer(buffer, Some(project), window, cx));
                    let markdown_preview: Entity<MarkdownPreviewView> = MarkdownPreviewView::new(
                        MarkdownPreviewMode::Default,
                        editor,
                        ws_handle,
                        language_registry,
                        window,
                        cx,
                    );
                    workspace.add_item_to_active_pane(
                        Box::new(markdown_preview),
                        None,
                        true,
                        window,
                        cx,
                    );
                    cx.notify();
                })
                .ok()
        })
        .await;
        if res.is_none() {
            workspace
                .update_in(cx, notify_release_notes_failed_to_show)
                .log_err();
        }
    })
    .detach();
}

#[derive(Clone)]
struct AnnouncementContent {
    heading: SharedString,
    description: SharedString,
    bullet_items: Vec<SharedString>,
    primary_action_label: SharedString,
    secondary_action_label: SharedString,
    primary_action_url: Option<SharedString>,
    primary_action_callback: Option<Arc<dyn Fn(&mut Window, &mut App) + Send + Sync>>,
    secondary_action_url: Option<SharedString>,
    on_dismiss: Option<Arc<dyn Fn(&mut App) + Send + Sync>>,
}

struct SkillsAnnouncement;

impl Dismissable for SkillsAnnouncement {
    const KEY: &'static str = "skills_announcement_dismissed";
}

fn announcement_for_version(version: &Version, cx: &App) -> Option<AnnouncementContent> {
    let version_with_skills = match ReleaseChannel::global(cx) {
        ReleaseChannel::Stable => Version::new(1, 4, 0),
        ReleaseChannel::Dev | ReleaseChannel::Nightly | ReleaseChannel::Preview => {
            Version::new(1, 4, 0)
        }
    };

    if *version >= version_with_skills && !SkillsAnnouncement::dismissed(cx) {
        // Only mention the Rules → Skills migration if the user actually
        // had Rules that got migrated. New users (and existing users who
        // never created a Rule) would otherwise be confused by a bullet
        // referring to "your rules" that don't exist.
        let migrated_anything =
            rules_to_skills_migration::migration_result().is_some_and(|result| !result.is_empty());

        let mut bullet_items: Vec<SharedString> = Vec::with_capacity(3);
        bullet_items
            .push(format!("Skills live in {GLOBAL_SKILLS_DIR_DISPLAY}/<name>/SKILL.md").into());
        bullet_items.push("Type / to manually invoke a skill".into());
        if migrated_anything {
            bullet_items.push(
                "The Rules Library is making way for skills: your default rules are now in a global AGENTS.md, and your other rules have been converted to skills".into(),
            );
        }

        Some(AnnouncementContent {
            heading: "Introducing Skills Support".into(),
            description: "Extend the agent with focused instructions and domain knowledge.".into(),
            bullet_items,
            primary_action_label: "Try Now".into(),
            secondary_action_label: "Read Documentation".into(),
            primary_action_url: None,
            primary_action_callback: Some(Arc::new(move |window, cx| {
                window.dispatch_action(Box::new(zed_actions::assistant::FocusAgent), cx);
            })),
            on_dismiss: Some(Arc::new(|cx| SkillsAnnouncement::set_dismissed(true, cx))),
            secondary_action_url: Some(zed_urls::skills_docs(cx).into()),
        })
    } else {
        None
    }
}

struct AnnouncementToastNotification {
    focus_handle: FocusHandle,
    content: AnnouncementContent,
}

impl AnnouncementToastNotification {
    fn new(content: AnnouncementContent, cx: &mut App) -> Self {
        Self {
            focus_handle: cx.focus_handle(),
            content,
        }
    }

    fn dismiss(&mut self, cx: &mut Context<Self>) {
        cx.emit(DismissEvent);
        if let Some(on_dismiss) = &self.content.on_dismiss {
            on_dismiss(cx);
        }
    }
}

impl Focusable for AnnouncementToastNotification {
    fn focus_handle(&self, _cx: &App) -> FocusHandle {
        self.focus_handle.clone()
    }
}

impl EventEmitter<DismissEvent> for AnnouncementToastNotification {}
impl EventEmitter<SuppressEvent> for AnnouncementToastNotification {}
impl Notification for AnnouncementToastNotification {}

impl Render for AnnouncementToastNotification {
    fn render(&mut self, _window: &mut Window, cx: &mut Context<Self>) -> impl IntoElement {
        AnnouncementToast::new()
            .illustration(SkillsIllustration::new())
            .heading(self.content.heading.clone())
            .description(self.content.description.clone())
            .bullet_items(
                self.content
                    .bullet_items
                    .iter()
                    .map(|item| ListBulletItem::new(item.clone())),
            )
            .primary_action_label(self.content.primary_action_label.clone())
            .secondary_action_label(self.content.secondary_action_label.clone())
            .primary_on_click(cx.listener({
                let url = self.content.primary_action_url.clone();
                let callback = self.content.primary_action_callback.clone();
                move |this, _, window, cx| {
                    telemetry::event!("Skills Announcement Main Click");
                    if let Some(callback) = &callback {
                        callback(window, cx);
                    }
                    if let Some(url) = &url {
                        cx.open_url(url);
                    }
                    this.dismiss(cx);
                }
            }))
            .secondary_on_click(cx.listener({
                let url = self.content.secondary_action_url.clone();
                move |_, _, _window, cx| {
                    telemetry::event!("Skills Announcement Secondary Click");
                    if let Some(url) = &url {
                        cx.open_url(url);
                    }
                }
            }))
            .dismiss_on_click(cx.listener(|this, _, _window, cx| {
                telemetry::event!("Skills Announcement Dismiss");
                this.dismiss(cx);
            }))
    }
}

struct UpdateNotification;

fn show_update_notification(cx: &mut App) {
    let Some(updater) = AutoUpdater::get(cx) else {
        return;
    };

    let mut version = updater.read(cx).current_version();
    version.pre = semver::Prerelease::EMPTY;
    version.build = semver::BuildMetadata::EMPTY;
    let app_name = ReleaseChannel::global(cx).display_name();

    if let Some(content) = announcement_for_version(&version, cx) {
        show_app_notification(
            NotificationId::unique::<UpdateNotification>(),
            cx,
            move |cx| cx.new(|cx| AnnouncementToastNotification::new(content.clone(), cx)),
        );
    } else {
        show_app_notification(
            NotificationId::unique::<UpdateNotification>(),
            cx,
            move |cx| {
                let workspace_handle = cx.entity().downgrade();
                cx.new(|cx| {
                    MessageNotification::new(format!("Updated to {app_name} {}", version), cx)
                        .primary_message("View Release Notes")
                        .primary_on_click(move |window, cx| {
                            if let Some(workspace) = workspace_handle.upgrade() {
                                workspace.update(cx, |workspace, cx| {
                                    crate::view_release_notes_locally(workspace, window, cx);
                                })
                            }
                            cx.emit(DismissEvent);
                        })
                        .show_suppress_button(false)
                })
            },
        );
    }
}

/// Shows a notification across all workspaces if an update was previously automatically installed
/// and this notification had not yet been shown.
pub fn notify_if_app_was_updated(cx: &mut App) {
    let Some(updater) = AutoUpdater::get(cx) else {
        return;
    };

    if let ReleaseChannel::Nightly = ReleaseChannel::global(cx) {
        return;
    }

    let should_show_notification = updater.read(cx).should_show_update_notification(cx);

    cx.spawn(async move |cx| {
        let should_show_notification = should_show_notification.await?;

        if should_show_notification {
            cx.update(|cx| {
                show_update_notification(cx);
                updater.update(cx, |updater, cx| {
                    updater
                        .set_should_show_update_notification(false, cx)
                        .detach_and_log_err(cx);
                });
            });
        }
        anyhow::Ok(())
    })
    .detach();
}